Coring device



Sept. 14, 1943. L.. L. sNYDER ET AL 2,329,225

CORING DEVI CE Filed Dec. 3, 1940 i r .S

INVENTORS upper end of the outer barrel.

Patented Sept. 14, 19u43 A coruna nevica,v

Leonardi.. Snyder, Montebello,- and Aladar Hole lander, Los Angeles, Calif., assignors to Byron i; Jackson Co., Huntington Park, Calif., a corporation of Delaware Application December 3, 1,940, Serial No. 368,332 (ci. Z55-412) `.16 Claims.

This invention relates generally to coring devices such as are employed in taking cores in oil wells and the like, and Ais directed particu.

larly to improvements in such devices whereby A more complete and cleaner cores may be obtained.

Core drills of the type employed in taking cores incidental to oil well drilling operations usually include an outer barrel secured to the lower end-of a drill string and having a coring bit attached toits lower extremity, andan inner l tween the inner barrel and the' throat of the venturi. This type Aof eduction device, when properly designed, is known to operate more ein barrel mounted within the outer barrel and having an open lower end adapted to receive the core as it is cut. The inner barrel is usually e spaced inwardly from the inner wall of the outer barrel to provide an annular circulation-space between the barrels through which drilling fluid iiows from the drill string to the discharge ports in the bit. An upwardly opening check valve is customarily provided at the upper end of the inner barrel to prevent the drilling uid from entering the inner barrel through its upper end, while at the same time permitting fluid to escape from the upper end ofthe inner barrel as the core enters the -lower end thereof.

. It has long been recognized that in order to obtain maximum'cor'e recovery, particularly in soft formations, the pressure `within the inner barrel Vmust be reduced materially -below the pressure of the drilling -iluid as it enters the `Thereason for this lies in the fact that the external pressure -in the well bore adjacent the lower end of the'4 inner barrel is considerably lower than the pressure of the drilling iiuid before it enters. the annular space between theVA barrels, due4 to the ciently than a jet type of nozzle because of the substantial reconversion of the velocity headback to pressure head on the downstream side of the Venturi passage. It has also proven to be more. eiective and more satisfactory in all respects than a jet type of nozzle for the present purpose. Examples of the use of Venturi passages vin innerA core barrels'are found in U. S. Letters Patents No. 2,076,063,.dated April 6, 1937, to Clarence E. Burt, and No. 2,108,949, dated February 22, 1938, to .Leonard L. Snyder.

In operation, the ratio of the iiuid velocity 'at the" throat of the venturi to that in'the annupressure'drop occasioned by the restricted any nular space between the barrels and the restricted discharge ports'in the bit. If the pressure within the inner barrel were allowed to remain equal to the pressure of the'drilling iiuid above the annular space between the barrels, it would exert substantial back-pressure on the core, resisting its entry into the inner barrel and in many instances resulting in greatly reduced core 'recovery. y

Various proposals have heretofore been made for reducing the pressure inthe inner barrel,A

such as, for example, by evacuating the upper end of the inner barrel by the use of ejector nozzles disposed in the stream civ-drilling fluid flowing past-the inner barrel. It has also been proposed to reduce the pressure in the inner barrel by the provision of a Venturi passage through which the drilling iiuid is constrained to flow, and by establishing'communication beprovide the desired constriction at the throat and a properly designed diverging discharge section while at the same time maintaining streamline ilow in the uid. Anyv abrupt deilection of the stream causes turbulence and eddies which not only decrease the efiicency of the device, but also resultin'rapid abrasion of the metal surfaces contacted by the abrasive liquid.

A principal object of this invention is to provide -an improved eduction device for core barrels, wherein the eduction eiort is increased and at the same time abrasion of parts is reduced to .a minimum'.

A further object is to provide an education device of simplified design permitting the easy replacement of parts subject to wear.

The manner in which these and other objects `are accomplished will become apparent from the following detailed description of a preferred embodiment of the invention, reference being had to the accompanying drawing wherein:

Fig. II is a fragmentary longitudinal sectional l View of a modiiied form of the invention;

Fig. III is a view similar to Fig. `1I illustrating a further modicatlon of the invention;

Fig. IV is a view of the device shown in Fig. III, taken in an axial plane at right angles to Fig. III; and

Fig. V is a fragmentary sectional view of a modication'of the device of Fig. I, adapted to use in a conventional core barrel.

Referring to Fig. I, the reference numeral I designates the upper portion of an outer barrel, which is adapted to be connected to the lower end of a drill string by a suitable sub, the lower portion of which is shown at II. The outer barrel is of suitable length to house an inner barrel I2, and is connected at its lower end to a core cutting bit (not shown). The lower end of the inner barrel I2 is open to receive the core as it is cut, and is adapted to seat on a shoulder in the bit in a conventional manner. In accordance with usual practice, the inner barrel is spaced inwardly from 4the inner wall of the outer barrel to provide an annular iiuid channel I3 between the barrels, through which drilling fluid is pumped downwardly to the bit.

Detachably secured to the upper extremity of the inner barrel I2, as by a threaded connection at I5, is an eduction device, generally designated I6, embodying novel features forming the subject matter of this invention. For purpose of illustration, the invention has been shown as incorporated in what is known as a wire-line core barrel adapted to be lowered from the surface through the drill stem and subsequently removed, with a core contained therein, by a wire line without removing the drill string. To permit the attachment of a wire line t0 the barbei when it is to be raised to the surface, a Spearhead Il of conventional shape is formed on the upper end of the eduction assembly and is adapted to be engaged by the usual overshot secured to the lower end of the wire line.

The eduction device I6 embodies as'its essential feature a Venturi passage having a constricted throat- 20 intermediate its ends and an elongated, gradually diverging discharge passage 2| therebelow. Inasmuch as the throat 20 constitutes the region of highest fluid velocity, the abrasion of the surfaces by the drilling fluid reaches a maximum at that point and for this reason we prefer to form the central portion of the device as a separate, replaceable throat piece 22. To facilitate the removal and replacement ci this part, the eduction device I6 comprises generally an upper section 23 and a lower section 243, interconnected by an intermediate sleeve p0rtion As shown, the sleeve is permanently secured to the upper section 23 as by welding at 2S, and is threadedly connected at 2l to the lower section-'24. The replaceable throat piece 22 is rigidly clamped between opposed shoulders 23 and 2S on the upper and lower sections 23 and 24, respectively, but may be removed upon disengagement of the threaded connection 21.

' A. pair or downwardly converging inlet ports 30 are provided in the upper section 23, and` a pair of similar but downwardly diverging ports 3| are provided in the lower section 24. It will be observed, that` .these ports are disposed/Yat a relatively small angleto the longitudinal axisof the device, in order to 'minimi/ef the 'deflection of thel stream of liquid and,thusavoideddiesiwhich cause rapid abrasion 'of the parts. The'entirej stream of ldrillingrluid is `vconstrained enter the upper 'ports 30 and ilowl through the venturi and d charge through the vlovwerports3Ifinto the annular space |3, by packing off the space I3 at a point intermediate the ports 30 and 3|.

In the illustrated embodiment, this is accomplished by a packer sleeve 32 seated in a recess 33 in the outer barrel I0 and bridging the annular space between the latter and the sleeve portion 25. Relative rotation between the packer sleeve and the outer barrel is prevented by a lock ring 34 suitably keyed to the barrel and having ratchet teeth 35 projecting upwardly therefrom into interlocking engagement with the packer ring.

From the description thus far, it will be apparent that as the'drilling fluid enters the Venturi passage its velocity is increased, due to the reduction in cross-sectional area of the stream, and reaches a maximum velocity in the constricted throat 20'; the pressure head is correspondingly reduced as the resultl of the conversion of pressure head into velocity head. During the passage of the uid from the throat 20 to the discharge ports 3|, the gradual increase in crosssectional area in the diverging passage 2| reconverts the major portion of the velocity head back to pressure head, and, because of the' high emciency of the Venturi device, the fluid enters the annular space I3 at a restored pressure which depends on the area of the space I3 and substantially unaffected by the temporary pressure drop in the throat 20. Thus, by establishing communication between the interior of the inner lbarrel I2 and the throat 20y the inner barrel may be vented into the stream of drilling fluid at a pressure materially below that prevailing in the annular space I3 between the inner and outer barrels. f

The manner in which the inner barrel is connected to the throat 20 constitutes a salient feature of our invention. An education conduit 40. of relatively small diameter, is mounted in a central bore 4| in the lowersection 24 and extends upwardly along the axis of the Venturi passage f to a point well above the throat v20. -In this form of the invention, its upper extremity is telescoped within a bore .42 in a` plug member 43 which in turn has a close sliding fit in a central bore 44 in the uppersection 23. lThe portion of the plug member below the bore 42 is counterbored to form an annular space 45 ybetween the conduit 40 and the depending skirt 46.

The conduit 40 is hollow throughout its length, and at its lower end communicates with a'port 48 leading to the interior of the inner barrel I2. A suitable check valve 49 is provided between the port 48 and the inner barrel, to prevent reverse flow of fluid while the inner barrel is being withdrawn to the surface of the well. The valve body also embodies a strainer 50 to exclude solids which might clog the conduit 40. Outlet ports 5| are formed in the conduit 48 above the lower edge of the skirt 46 for the purpose of establishing communication between the conduit and the annular channel 45. It will be observed that the outer wall of the lower portionof the skirt 46 is tapered downwardly, terminating in a relatively sharp lower edge 52. The eduction conduit 40 thus discharges into the throat 20 of the Venturi passage in a direction parallel to the direction of ilow-ofthe main streamof drilling fluid,`=theskirt casa-forming ini'efrectran nnuiarf eductinineztzle. @The pressure wit-matrici nn'uiar cnanneifisfbez-fatwenthefskirtf'aeianuf'thefconduitluiisiithusfreduceotelw thatrinfthefthr'atizuffrsyfa :r1-cunt @ifequalltcethefiveloc'itycheadiocftheamain cream vimpassing throughrth throat. f'lnasmcli'ras'fthe 75l-static pressure head ofithevdrilling ihiidlfhasalready been substantially reduced at the throat of the venturi, it will be apparent that the total reduction in pressure in the eduction conduit 40 is equal to the combined effect of the Venturi device I6 and the eduction nozzle 46. This pressure drop is suicient, in actual practice; to more than ofiset the friction loss in the annular channel |3 and in the discharge passages in the bit, and hence the pressure in the inner barrel |2 is reduced belowthe external pressure prevailing in the well bore. Resistance to entry of the core into the inner barrel is eliminated, and the core is in many instances actually drawn by suction into the barrel. Cleaner, more complete cores are thus obtained.

Aside from its increased hydraulic eciency, the device shown in Fig. I is characterized by other features of advantage. It will be observed that the parts dening the Venturi passage are symmetrical with respect to the passage, thus promoting streamline flow through the passage and avoiding eddies and their consequent abrasive effect on the exposed surfaces. The central throat 22, the eduction conduit 40, and the plug member 43, which are subject to the maximum wear, are all readily replaceable and are of simple, inexpensive construction. By separating the threaded connection at 21, the upper and lower section 23 and 24 may be separated, permitting the easy removal and replacement of the three above-mentioned parts.

In Fig. II we have shown a modified form of Venturi device which dilers from that illustrated in Fig. I principally by the omission of the skirt 4B from the eduction conduit 40 and the consequent elimination of the eduction nozzle effect of that element. The device comprises upper and `relation by a sleeve 84.

its eduction nozzle effect. However; the device of Fig. II possesses the other advantages of the rst described form over prior devicesthat is, the reduction of abrasive action to a minimum by the symmetrical construction, the simplified and inexpensive construction, and the easy replacement of the eduction conduit and the throat piece.

A still further modification is illustrated in Figs. III and IV. This form of the invention embodies the combined Venturi passage and eduction nozzle of Fig. I, the central eduction conduit being replaced by eduction passages extending upwardly through .the wall surrounding the Venm turi passage. Upper and lower sections 8| and 82 and an intermediate throat piece 83, having a constricted throat 83 are secured in end-to-end The latter is permanently secured to the lower section 82, as by welding at 85, and extends upwardly past the discharge ports 86, around the throat piece 83, past the inlet ports 81, and is threadedly connected to the upper section 8| at 88. The Venturi device is threadedly connected at 89 te the upper end Of an inner barrel 90.

In this embodiment of the invention a modi# ed arrangement is provided for connecting the interior of the inner barrel in communication with the throat of the Venturi passage. Extending upwardly within the lower section 82 from the usual check valve and strainer body 92 is a central passage 93, which terminates at its upper end within the body of the section 82. A pair of diametrically opposite branch passages 94 and 95 (Fig. IV) extend upwardlyand outwardly from the central passage 93 to the outer periphery of the section, and communicate with longitudinal passages 96 and 91, respectively, ex-

lower sections 6| and 62, connected together by an intermediate section 63 permanently secured to the lower section and threadedly connected at 84 to the upper section. The lower .section 62 is adapted to be connected to the upper end of a core barrel as in Fig. I. A-replaceable throat piece 61, having a constricted throat 61a, is clamped between opposing 'shoulders 68 and 69 on the upper and lower sections, respectively, and thus may be quickly and easily replaced when the threaded connection 64 is broken.

An eduction conduit 10 is seated at its opposite ends in aligned bores ,1| and 12 in the sections 6| and 62, and extends through the throat piece 61 'Y in coaxial relation thereto. The interior of the conduit communicates at its lower end with the inner barrel by way of the passage 13 and` preferably through an upwardly opening check valve and a strainer, as in Fig. I. In this embodiment, however, the interior of the conduit 10 communicates directly with the throat|1aL through ports 15, which are preferably inclined at a slight downward angle so as to discharge into the main ,stream of drilling liuid in the general direction of flow of the latter.

The Venturi device of Fig. II functions in a manner similar to that of Fig. I, the pressure within the throat 61a being reduced below that of the drilling fluid above and below the Venturi passage by the conversion of a portion of the pressure head into velocity head in the throat of the passage, and the subsequent reconversion of substantially all of the increased velocity head back to pressure head in the gradually diverging discharge portion 11. This device is incapable of effecting as great a pressure drop in the inner barrel 66 as is the device of Fig. I, in view of the omission of the skirt 46 of the latter gure and wall of the sleeve 84.

At the upper extremities of the passages and 91 a second pair of branch passages 98 and 99 vextend upwardly and inwardly to a central passage |00 formed in the upper section 8|. The passage |00 is closed at its upper end and is threaded at its lower end to receive the upper threaded end of an eduction nozzle member |0I, which extends downwardly along the axis of the Venturi passage' to a point adjacent the throat 83a. The lower portion of the nozzle member |0| is tapered downwardly and term.nates in a relatively thin edge at |02, to avoid an abrupt change in cross sectional area of the iiuid stream at that point.

From the foregoing description of this modification, it will be apparent that the inner barrel 90 is vented to the throat 93 through the Ypassages 93, 94, 95, 96, 91, 98, 99 and |00, and the nozzle member |95, and that the pressure within the member ll'il will be lower than the pressure y of the drilling iluid at the discharge port 86 by an amount equal to the combined pressure drop eiected by the Venturi passage and the eduction nozzle. This form of the invention is slightly more complicated than the other .two forms from a manufacturing standpoint, but is more effective in reducing the pressure in the inner barrel.

This is because of the elimination of the central eduction conduit extending through the Venturi passage, thus making it possible to achievethe maximum suction effect on the open end of the eduction nozzle IUI.

In Fig. V We have shown a slightly modified form of the embodiment illustrated in Fig. I, the modifications being only those necessary to adapt the device of Fig. I to use in conjunction with a conventional core barrel. The term conventional core barrel is commonly used to denote a well coring assembly in which the inner, corereceiving barrel is secured within the outer barrel and is lowered into the well and removed therefrom with the outer barrel, in contradistinction to a wire line assembly such as shown in Fig. 1. A Spearhead is not required on the inner barrel of a conventional core barrel assembly, and hence the upper section 23 and its lateral inlet ports 30 of Fig. I may be dispensed with, thus.. providing an unobstructed central fluid passageway leading downwardly to the Ven,- turi device. K

In the modified Venturi device shown in Fig. V, a lower section H is suitably secured at its lower end to the upper end of an inner barrel (not shown) and is threadedly connected at its upptr end to a sleeve member III. The latter is permanently secured, as by welding at ||2, to the lower end of an upper section II3. A throat piece I|4 is detachably clamped between opposing shoulders I I5 and I I6 on the upper and lower sections, respectively, and has a. constricted throat III intermediate its ends.V Below the throat II'I, a diverging discharge passage IIB extends downwardly to lateral discharge ports IIS in the lower section. An eduction conduit |20 is mounted 'in the lower section and extends upwardly along the axis of the Venturi passage to a point Well above the throat III. Mounted on the upper extremity of the conduit is a plug member |2| having a bore |22 to receive the conduit; and a counterbore |23 forming a depending skirt portion |24 spaced from the conduit by an annular channel |25. Suitable outlet ports |26 are Yformed in the wall of the conduit in the up,- per portion of the counterbore, whereby fluid passing upwardly within the conduit is discharged into the channel |25 and thence into the throat ||`I in the direction of` flow of drilling fluid through the Venturi passage. The interior of the conduit communicates with the inner bar-l rel in a manner similar to that shown in Fig. I.

Thus far the device is in all respects similar to the device of Fig. I. The upper section I I 3, however, merges upwardly into an annular tube |30 which is open at its upper end and is mounted centrally within the outer barrel |3I to present a central, unobstructed passage leading to the Venturi passage. The eduction conduit |20 in this instance is supported only at its lower end in the 'lower section III), and the upper extremity of the plug member |2I converges upwardly, as shown at |32, in order to provide streamline flow of drilling fluid from the central passage into the annular Venturi passage. g

All of the advantages of the device of Fig. I are also inherent in the modified device shown in Fig. V, including the combined pressure reduction resulting from the Venturi passage and the eduction nozzle effect of the annular discharge channel 25. The parts which are subject to the most wear are easily replaceable and are of simple and inexpensive construction.

Although we have shown and described in deasaaaas tail severalspecii'lc forms which the invention may assume, it is to be understood that the invention isznot limited to the details of construction shown therein, but is of the full scope of the appended claims.

-We claim: o y

1. A device foruse in combination with a core drill of the type having an outer barrel secured to the lower end of a drill stem and a core barrel mounted within the outer barrel, comprising: an elongated body mounted on the upper portion of the core barrel and having a Venturi vpassage formed therein in the path of drilling fluid in said drill stem; and means communicating said bore barrel withthe throat of said Venturi passage, comprising an eduction conduit extending coaxially within the Venturi passage and having communicationat one end with the interior of Y the core barrel and having an opening at the throat of` the Venturi passage.

2. A device for use in combination with a core drill having an outer barrel connected to the lower end of a drill stem and an inner core barrel mounted within the o uter barrel, comprising: an elongated body mounted on. theupper portion of the inner barrel and having a passage therein in the path ofr drilling fluid circulated downwardly through the drill stem, said passage including a restricted throat portion and a gradually diverging portion on the downstream side ofthe throat portion; and means establishing communication between the inner barrel and said restricted throat portion comprisingv a' conduit member mounted in said body and extending into said passage in coaxial relation thereto and opening Into the throat portion thereof, and passage meansconnecting said conduit member with the interior of the inner barrel.

3. A core barrel venting device for core drills, comprisingz. a. `lower body member adapted to be mounted on the upper portionof a core barrel and having acentral opening therein and adischarge port leading therefrom; an upper body member mounted above said lower body member and having an inlet port and a central opening therein; an intermediate member mounted'between said body members. and having a .central opening includingA a restricted` throat portion; means detachably securing said body members and said intermediate member together with their openings in alignment to form a passage extending from said inlet port tosaid discharge port; and means communicating said core barrel with the throat portion of said intermediate member, comprising a conduit member extending coaxially within said passage and having an opening therein communieating with said throat portion, and passage means connecting said conduit member with the interior of the core barrel.

4. A core barrel venting device as set forth in claim 3, in which said conduit member is supported at opposite ends thereof by said body memclaim 3, in which" said intermediate member isy clamped between opposing shoulders on said body members.

7. A core barrel venting device as set forth in claim 3, in which said means for detachably securing said body members and said intermediate member together comprises a sleeve member surrounding said intermediate member and connected at opposite ends to said body members, at least one of said connections being readily releasable.

8. In a core barrel venting device for core drills, means for relieving the core barrel of the pressure of the drilling fluid circulated past said venting device, comprising: a body member mounted on the upper portion of the core barrel and having a Venturi passage formed therein in the path of the drilling fluid; an eduction conduit mounted in said Venturi passage and having an outlet disposed in the restricted throat thereof and facing in the direction of ow. of drilling uid .in said sockets and extending coaxially through through 'the passage; and passage means conv-V ,v

necting the inlet end of the eduction conduit with the interior of the core barrel. p

9. In a device of thecharacter described, the combination of a body adapted to be mounted .on

the upper portion of a core barreland having a the passage and facing the discharge end of the passage, and passage means communicating the inlet end of the eduction nozzle member with the interior of the core barrel. A

10. A device as set forth in claim 9, in which said passage means comprises conduit means extending from the core barrel coaxially through said Venturi passage and telescopically within said eduction nozzle member, and having an outlet communicating with said nozzle member.

1l. A device as set forth in claim 9, in which said passage means is defined by walls extending through said body from the core barrel to the remote end of said Venturi passage.

12. In a device of the character described, the combination of a body adapted to be mounted on the upper portion of a core barrel and having a Venturi passage formed therein, said body having aligned bores at opposite ends of said Venturi passage and coaxial therewith, passage means communicating one of said bores with the interior of said core barrel, an eduction conduit mounted in the other bore and having an outlet at the throat of the Venturi passage, and passage'means connecting the inlet end ofsaid eduction conduit with the first-named bore.

said Venturi passage, said conduit member having an outlet communicating with the throat of the Venturi'passage and an inlt communicating with the interior of the core barrel.

14. A device as set forth in claim 13, in which said -conduit member includes a skirt surrounding said outlet and terminating at the Venturi throat, said skirt being spaced from the conduit member to form an annular channel therebetween extending from the outlet to the Venturi throat and facing in the direction of iluid flow through the throat.

15. In a device of the character described, the combination of a body adapted to be mounted on the upper portion of a core barrel and having a Venturi passage formed therein, said body comprising separable sections detachably secured together and having opposed sockets therein at opposite ends of and coaxial with said Venturi passage, passage means connecting said core barrel with the adjacent one of said sockets, a plug memberhaving one end thereof mounted in the other socket and having an axial bore extending from the other end at least partially therethrough, a conduit member having one end thereof mounted in said first-named socket and having its other end mounted inthe bore in said plug member, said conduit member having a lateral outlet adjacent said other end, and said plug member having a skirt surrounding said outlet.

16. A device as set forth in claim 9, in which said body is provided with a centrally disposed inlet and an axial iiuid passageway leading from the inlet to the Venturi passage, and in which said eduction nozzle member includes a closed' upper end disposed coaxially within the iiuid passageway and tapered upwardly to divert the fluid into the Venturi passage with a minimum of disturbance,

LEONARD L. SNYDER.. ALADAR HOLLANDER.

.pat-.ent No. 2,529,225.

CERTIFICATE oF CORRECTION. i

September llI, 19115. LEONARD L. SNYDER,ET AL.'

It is hereby certified that error appears in the printed speciiication of the above numberedpatent requiring correction 'as follows: Page l, second column, line59, for "effort" read --effect--g line'li, and ijagefZ, second column, line 58, for "education" read -eduction'-; page 5, first column, line 2h, for"throat 22". read --throat piece 22e-; and' secondt column, line b9, for "passages 90 read passages 96-; page 1|., firstc-olpmn, 1ine72,

for 'channel 25" read --channel' 125; and second column, line-lh, claiml, for "bor'e'l read --coIe-; and ,that the said Letters Patent shouldbe read with this correction therein that the same may conform to the record of the case `:in the Patent Office.

signed and sealed this 9th day of Novembexyi. D. 1915.

Henry vanv Arsdale (Seal) Acting Commissione of Patents. 

